Extracted Text

The following text was automatically extracted from the image on this page using optical character recognition software:

SLAC-PUB-11924June 2006Reflectivity Measurements for Copper and Aluminum in the Far Infraredand the Resistive Wall Impedance in the LCLS UndulatorK.L.F. Bane, G. Stupakov, SLAC, Stanford, CA 94309J.J. Tu, Department of Physics, The City College of New York, New York, NY 10031Reflectivity measurements in the far infrared, performed on aluminum and copper samples, are presented and analyzed.Over a frequency range of interest for the LCLS bunch, the data is fit to the free-electron model, and to one includingthe anomalous skin effect. The models fit well, yielding parameters dc conductivity and relaxation times that are within30-40% of expected values. We show that the induced energy in the LCLS undulator region is relatively insensitive tovariations on this order, and thus we can have confidence that the wake effect will be close to what is expected.Presented at the European Particle Accelerator Conference (EPAC 06),Edinburgh, Scotland, June 26-30, 2006